1. Field of the Invention
The present invention relates to a voice-protected, frequency-selective signal receiver for telecommunication systems, in particular telephone systems, in which the signals to be received consist of several simultaneously occurring individual frequencies.
2. Description of the Prior Art
In telephony the dialing and signaling tasks are accomplished with the aid of multi-frequency code signals, with each signal consisting of a combination of two frequencies. In accordance with the particular code utilized, previously known receivers operate with filter arrangements for separating the frequency components, which are substantially further processed on an individual basis. Because of the high requirements with respect to mutual blocking attenuation, for example because of necessary voice protection measures, filters of relatively great slope are required, which filters are very expensive to produce and require considerable space.